3 hours, 35 minutes, and 21 seconds is a pretty respectable marathon time, generally speaking. Running that time on a treadmill that you’re literally strapped to in space? Timothy Peake, a British astronaut, pulled that off on Sunday, and we’re impressed.

It was the day of the London Marathon (read more about that here) and Peake participated from rougly 200 miles above the other 38,000 runners who laced up at the Greenwich start line. Using an app called RunSocial, Peake viewed the course on an iPad from the International Space Station treadmill. (Peake’s view of the streets sped up and slowed down according to his pace—he started out at a conservative 7.5mph and ramped up to 9mph for the last 10k of the run, per The Guardian).

But Peake faced a slightly different challenge than the Earth-bound marathoners. Because he was literally strapped to the treadmill via a harness, Peake also used different muscles than he would have on earth. The harness put the weight directly on Peake’s hips and shoulders, The Guardianreports. The straps also dug into his skin, causing abrasions and pressure sores after just 40 minutes of running (only three hours to go!)

So, even though Peake was only felt 70 percent of his simulated bodyweight, he hardly had an “easier” go of it.